The 4th International Symposium on Mine Safety Science and Engineering (ISMSSE2018)

375 / 2018-06-01 11:43:31

Catalytic Characteristics of Ni Metal on Decomposition of Sodium Chlorate in Emergency Oxygen Generators

mine rescue,oxygen generators,sodium chlorate,catalytic decomposition

Mine Safety Science Theory and Emergency Rescue > Mine emergency rescue

Chemical oxygen generators are used widely for emergency oxygen supply in aircraft, spacecraft, submarines, and mine rescue. However, the problems of the fluctuation of oxygen production rate and the amount of heat released from the combustion process are the main reasons restricting its wider application. Therefore, exploring high effective catalysts to the decomposition of sodium chlorate, the oxygen source of oxygen generators, have attracted much attention. In this study, the catalytic of Ni metals in different size distribution on decomposition of sodium chlorate was investigated used thermogravimetric analysis. Before the experiment, the SEM and particle size of Ni metals were measured, and the mean size of Ni metal are 64 nm, 75 nm, and 10 µm, respectively. The thermogravimetric experiments of the mixtures of Ni metals (at 4 % mass ratio) and NaClO3 are conducted using Netzsch STA499F3 at the heating rate of 10 ℃/min, and the TG/DTG/DTA data were simultaneously monitored in argon flow atmosphere of 40 ml/min. The study results showed: (1) Ni metal have significant catalytic on the decomposition of sodium chlorate, and its efficiency determined by the particle size distribution, i.e., the smaller the particle size, the higher the catalytic efficiency; (2) In addition, the large size of Ni metal (mean size ≥ 10 µm) can lead to the instability decomposition of sodium chlorate, and peak of DTG curves increases from one to two, and the decomposition process becomes discontinuous; (3) The maximum decomposition rate (MDR) of sodium chlorate is also related to the particle size of Ni metal, as decreased from 10 µm to 65 nm of Ni metals, the MDR decreases first and then increases, and the curves show a “V” shape.